Is your dog drinking more water, panting excessively, losing fur, or having a pot-bellied appearance? These could be signs of Cushing’s syndrome, a condition where there is excess cortisol in the body.
This most often happens because of a tumour in the pituitary gland. It can be treated and managed with medication, surgery, and in some cases radiation therapy.
Understanding Cushing’s Disease in Dogs
Also known as hyperadrenocorticism, Cushing’s syndrome is an endocrine disorder where the body has too much of a hormone called cortisol for a prolonged period of time. It can be serious if it is not treated. The condition is named after Dr. Harvey Cushing, the brain surgeon who first described it in humans.
Elevated cortisol may be caused by either internal sources such as tumours, or external sources like corticosteroid medications. Cushing’s syndrome is a broad term encompassing all causes of excess cortisol.
One specific cause of Cushing’s syndrome is called Cushing’s disease. This occurs when a tumour, usually a benign adenoma, in the dog’s pituitary gland produces excess hormones that then stimulate the adrenal glands to make too much cortisol. The pituitary gland is located at the base of the brain, while the adrenal glands are just above the kidneys.
Less frequently, a tumour in one of the adrenal glands themselves can also cause Cushing’s syndrome. These may be benign (adenomas) or malignant (carcinomas).
Common signs of a dog who has too much cortisol in their body include increased thirst and urination, excessive hunger, excessive panting, a pot-bellied appearance, hair loss, skin changes, muscle weakness, and recurrent skin or urinary infections.
There are treatments available that can lower or inhibit cortisol levels in canine patients and help manage their symptoms. The sooner your veterinarian can diagnose the condition and start treatment, the better your pet’s chances at an improved quality of life.
If left untreated, Cushing’s can lead to serious complications such as recurring infections (e.g., skin or urinary tract), high blood pressure, diabetes, blood clots, as well as progressive muscle and organ changes such as liver enlargement (hepatomegaly) and muscle wasting.
Dogs are the primary species affected by the condition. In particular, it is much more common in middle-aged to older dogs.
While cats can also develop Cushing’s disease, it is rare and may present somewhat differently. In cats, the condition is often associated with diabetes, sometimes presenting with fragile, thin skin.
What is Cortisol?
Cortisol is a hormone produced by the adrenal glands, which sit just above the kidneys.
It has vital functions in helping the body respond to stress and also regulates many processes, such as metabolism, immune response, blood pressure, and blood sugar balance.
While normal levels of cortisol are essential for general health, too much cortisol over time can cause significant problems.
Signs of Cushing’s Disease and Cushing’s Syndrome in Dogs
As excess cortisol affects various body systems, dogs with Cushing’s may develop a wide range of symptoms. If you recognise these signs, please seek veterinary consultation and care from a trusted vet clinic or animal hospital.
Common symptoms in a dog with Cushing’s syndrome include:
Behavioural changes:
- Increased thirst or drinking (polydipsia)
- Increased urination (polyuria)
- Increased appetite (polyphagia)
- Excessive panting
- Lethargy and weakness
Changes in appearance:
- Pot belly, rounded enlarged abdomen, bloated look
- Hair loss (alopecia): thinning fur or bald patches, especially along the sides, tail, and belly
- Thinning of the skin, which may heal poorly and sometimes show darkened pigmentation
- Formation of calcium deposits in the skin (calcinosis cutis) that can appear as hard, raised nodules
Although many of these signs can be subtle or develop gradually, if you notice several of them together, it is important to have your dog evaluated by a veterinarian.
For questions or to book an appointment, please WhatsApp our friendly veterinary team at 8891 4417 (Upper Thomson) or 8809 0787 (Yishun).
Main Causes of Canine Cushing’s Syndrome
Cushing’s syndrome in dogs is due to prolonged high levels of the hormone cortisol in the body. Two primary causes of such excess cortisol are 1) pituitary-dependent Cushing’s disease and 2) adrenal-dependent Cushing’s syndrome.
1. Pituitary-dependent Cushing’s disease: Most typically seen in canine patients, it happens when a tumour (usually a benign adenoma) in the dog’s pituitary gland produces too much of a hormone called ACTH (adrenocortocotropic hormone). This hormone in turn overstimulates the adrenal glands to release too much cortisol.
Pituitary tumours are the most common cause of Cushing’s syndrome in dogs, accounting for about 80% to 85% of cases.
2. Adrenal-dependent Cushing’s syndrome: Less commonly, adrenal tumours can directly cause Cushing’s by producing excess cortisol independently, without pituitary involvement. These adrenal tumours can be either benign or malignant, and they account for around 15% of Cushing’s syndrome cases in dogs.
3. Other causes: While rare, other factors that may result in Cushing’s in dogs include the long-term use of corticosteroid medications (be it oral, injectable, or topical). These drug-induced cases are known as iatrogenic Cushing’s syndrome.
Which Dogs Are More at Risk of Cushing’s Disease?
The condition is most commonly diagnosed in middle-aged to senior dogs, usually those over 6 years of age. On average, many cases are first detected when the patient is around 10 to 11 years old.
Some breeds have been reported more frequently as developing Cushing’s, including:
- Bichon Frise
- Border Terrier
- Boxer
- Cavalier King Charles Spaniel
- Dachshund
- Miniature Schnauzer
- Pomeranian
- Poodle
- Shih-Tzu
- Yorkshire Terrier
Some smaller to medium-sized breeds are often observed as higher risk or overrepresented in cases of pituitary-dependent Cushing’s disease.
That said, please keep in mind that any breed or mixed-breed dog can develop Cushing’s syndrome, and a clear genetic predisposition has not been established.
Regular vet checkups and monitoring for symptoms can help with timely diagnosis and management, particularly for at-risk groups.
Veterinary Diagnosis of Cushing’s in Canine Patients
Diagnosing Cushing’s syndrome will depend on the presentation of clinical signs in the dog and the results of comprehensive testing at the veterinary clinic.
This typically starts with a physical examination. The vet will also speak with you about what symptoms are present and when they began.
If your veterinarian suspects Cushing’s, baseline tests such as a complete blood count (CBC), serum chemistry panel, and urinalysis are often recommended. While these cannot confirm Cushing’s, they may reveal patterns suggestive of it, e.g., increased liver enzymes, dilute urine, or secondary urinary tract infections.
Specialised blood tests could include the Low Dose Dexamethasone Suppression Test (LDDST) or the Adrenocorticotropic Hormone (ACTH) Stimulation Test. In most cases, the LDDST is generally the preferred screening test for Cushing’s in dogs.
Advanced diagnostic testing may include an abdominal ultrasound to help identify tumours, assess the size and shape of the adrenal glands, as well as examine the liver, gall bladder, and other abdominal organs. Ultrasound findings can also help distinguish between pituitary-dependent and adrenal-dependent forms of the disease. Chest X-rays could be recommended if your dog has breathing issues or if there is concern about tumour spread.
Accurate diagnosis by an AVS-licensed veterinarian in Singapore is important to determine the most suitable treatment plan for your pet and ensure the best possible outcome.
For questions or to book an appointment, please WhatsApp our friendly veterinary team at 8891 4417 (Upper Thomson) or 8809 0787 (Yishun).
What Are The Treatment Options for Cushing’s in Dogs?
Treatment can help to slow the progression of the disease and improve your pet’s quality of life. In most cases, especially with pituitary-depending Cushing’s, the condition is managed rather than cured, requiring lifelong treatment and monitoring. In some adrenal tumour cases, surgery might be curative if the tumour is benign and fully removed surgically.
The primary goal of treatment for Cushing’s disease or syndrome is to control the cortisol levels and manage the symptoms without suppressing cortisol too much.
Depending on each case and the specific underlying cause, potential treatment options include medication, surgery, radiation therapy, or a combination. In addition, dietary adjustments, such as a lower-fat diet, could be beneficial for dogs with pancreatitis, elevated blood lipids, or obesity, which can occur alongside Cushing’s.
Veterinarians might prescribe medications such as trilostane, which blocks an enzyme involved in hormone synthesis, to decrease production of cortisol; or mitotane, which destroys adrenal tissue that make cortisol.
For adrenal-dependent Cushing’s syndrome, abdominal surgery is typically required to remove the entire tumour, depending on the type of adrenal gland tumour and the dog’s general health. If surgery is not possible, medication can be an option for some patients.
Radiation therapy, albeit less common, may be used for large pituitary tumours (macroadenomas) to shrink the tumour, improve neurological signs, and help restore hormonal balance.
For iatrogenic Cushing’s syndrome, which results from prolonged corticosteroid use, treatment involves gradually tapering and discontinuing the steroid medication under veterinary supervision.
It is important to discuss with your veterinarian about the possible risks and side effects of the treatment options. Clear communication between the pet owner and the veterinary team is crucial to ensure informed decisions are made for the well-being of the patient.
Prognosis for Dogs with Cushing’s Disease
The prognosis for dogs diagnosed with Cushing’s syndrome varies depending on the cause, severity of symptoms, how quickly treatment begins, and whether they have any other underlying health issues.
With proper veterinary care and careful management, many dogs live comfortable, extended lives despite the condition.
Dogs with pituitary-dependent Cushing’s disease, the most common form, can often be managed successfully for several years with medication. The median survival times for dogs with this form of the condition and treated with trilostane medication, is estimated to be around 2 to 3 years, though many live longer with good management.
Regular monitoring and pet checkups can help the veterinarian adjust treatment and detect any complications early.
For adrenal tumours causing Cushing’s, the outlook depends on whether the tumour is benign or malignant, and whether it has spread. Dogs with benign adrenal tumours that are surgically removed may have a normal life expectancy. However, malignant adrenal tumours have a guarded to poor prognosis, especially if metastatic (i.e., the cancer cells spread to other areas of the body).
Concerned About Cushing’s? Chat With Us
While Cushing’s is often a chronic condition, a timely and accurate diagnosis as well as an appropriate, tailored treatment plan can greatly improve your dog’s quality of life and reduce the risk of serious complications.
At Paws N’ Claws Veterinary Surgery in Singapore, both our clinic branches are fully equipped with in-house sterile surgical theatres, advanced diagnostics, imaging scans such as X-ray and ultrasound, hospitalisation facilities with overnight monitoring, and pet emergency care.
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